Software defined networking (SDN) comprises a plurality of hosts in communication over a physical network infrastructure, each host having one or more virtualized endpoints such as virtual machines (VMs) or containers that are connected to logical overlay networks that may span multiple hosts and are decoupled from the underlying physical network infrastructure. One common characteristic of software defined networking is a separation of the control plane from the data plane. The control plane is concerned with determining the logical overlay network topology and maintaining information about network entities such as logical switches, logical routers, and endpoints, etc. The logical topology information is translated by the control plane into network configuration data that is then communicated to network elements of each host. The network configuration data, for example, includes forwarding table entries to populate forwarding tables at virtual switche(s) provided by the hypervisor (i.e., virtualization software) deployed on each host. In some cases, the control plane may need to transmit the network configuration data, or other types of data, to one or more VMs running on the virtualization software of a host.
An example of this is when SDN is integrated with solutions such as platform as a service (PAAS) and container as a service (CAAS) to provide native network support to containers that are created within various virtual machines on a hypervisor. Platform as a service (PAAS) and container as a service (CAAS) solutions like Cloud Foundry, Kubernetes, and Openshift provide application level abstractions that allow developers to deploy, manage, and scale their applications. PAAS is a service that provides a platform that allows users to develop, run, and manage applications without the complexity of building and maintaining the infrastructure typically associated with launching an application. For example, a user can control software deployment with minimal configuration options, while the PAAS provides services to host the user's application. CAAS is a form of container-based virtualization in which container engines, orchestration, and the underlying compute resources are delivered to users as a service from a cloud provider. These solutions provide support for compute and storage but do not provide any native networking support. As such, SDN is utilized to provide networking for the containers. For example, after a new container is scheduled for creation, the SDN control plane generates network interface configuration data that can be used by the container host VM (i.e., the VM hosting the container) to configure a network interface for the container. The configured network interface for the container enables network communication between the container and other network entities, including containers hosted by other VMs on the same or different hosts. In order for the host VM to set up a network interface for a new container, the host VM may require access to the network interface configuration data generated for the container by the SDN control plane. In some cases, some PaaS and CaaS solutions may provide a mechanism to send the network interface configuration data to the host VM. However, other PaaS and CaaS solutions may not provide such a mechanism.